Brush with self-locking detachable head portion



Oct. 11, 1966 s. MCNAIR ET AL 3,277,509

BRUSH WITH SELF-LOCKING DETACHABLE HEAD PORTION Filed Oct. 8, 1964 l BY I /v 5' qe/ f ATTORNEYS.

United States Patent Oice 3,277,509 Patented Oct. 11, 1966 3,277,509 BRUSH WITH SELF-LOCKING DETACHABLE HEAD PORTION Samuel L. McNair, Long Beach, and Karl Sator, Anaheim, Calif., assignors to The Songrand Corporation, Kansas City, Mo., a corporation of Missouri Filed Oct. 8, 1964, Ser. No. 402,416 Claims. (Cl. 15-176) This invention relates generally to brushes and refers more particularly to an improved construction for brushes of the hair brush type having a removable or detachable brush head.

Removable brush heads are old in the art. Mazella Patent No. 1,894,882, discloses a typical arrangement, the brush head being held in position through a dovetailed joint which permits `disassembly of the brush head from the back whenever desired by simply sliding the head longitudinally olf the back. However, such joints often lose their initial tight iit which means that ordinarily a positive releasable latch must be provided to prevent the brush head from accidentally working loose. Even then, the lat-ch solution is not entirely satisfactory. It will not prevent wobble of the brush head as progressive looseness occurs in the joint and it complicates considerably the manufacture and assembly operations, since additional parts and connections are required. In addition, it leaves a good deal to be desired from the standpoint of esthetics.

An important object of the instant invention is to provide a brush of the hair brush type having a removable brush head in which a sliding dovetailed joint is provided between the brush head and back, yet in which the connections between the -components of the dovetail is maintained frictionally tight despite wear and length of service and which has a snap type locking means for preventing accidental displacement of the brush head. It is a special feature of the invention that the resistance to separation of the brush head from the back is great enough that it serves as well as a latch to hold the parts together. However, it is not so tight that the brush head cannot, when desired, be easily removed for purposes of cleansing or replacement.

A further object of the invention is to provide a construction for a brush having the advantages noted above and which is peculiarly suitable for incorporation in electrically powered vibrating hair brushes. The improved connection between the brush head and back provided by this invention assures that the brush head will not be separated from the back under influence of the vibrations -of the unit during the use.

Still another object of the invention is t-o provide a simple and elfective resilient biasing force in a dovetailed joint which increases the frictional resistance to sliding separation of the components of the joint, and which serves to bias the components together so that a detent lock means will operate satisfactorily. The inventive structure is especially suitable for incorporation in molded plastic brushes having a hollow back.

Other and further objects of the invention, together with the features of novelty appurtenant thereto will appear in the course of the following description.

In the accompanying drawing, which forms a part of the specication and is to be read in conjunction therewith, and in which like reference numerals indicate like parts in the various views:

FIG. 1 is a side elevation of .a preferred brush construction embodying the invention;

FIG. 2 is a top plan of the brush, the upper portion of the brush back being broken away to expose the interior structure;

FIG. 3 is a fragmentary bottom plan of the brush back with the brush head removed therefrom to expose the lower side of the brush back;

FIG. 4 is a view similar to FIG. 1 but showing the removable brush head in central longitudinal section;

FIG. 5 is a sectional view taken along the line 5 5 of FIG. 4in the direction of the arrows; and

FIG. 6 is an enlarged fragmentary section showing in `greater detail the detent means for holding the brush head `against displacement during normal use.

Referring to the drawings, reefrence numeral 10 indicates generally the combined brush back and handle. This is made up of upper and lower shell sections 11 and 12, respectively, which are joined along the horizontal line of intersection 13. These sections preferably are molded from a suitable plastic `and are thin walled, providing a hollow interior.

The brush which is illustrated is an electrically vibratable brush. It is provided with an internal vibrator motor 13 which is preferably constructed in accordance with the disclosure of Martin I. Stam, application Serial No. 276,- 258, for Vibrator Motor, filed Apr. 29, 1963, now Patent No. 3,155,854. Since the details of the motor do not form any part in the present invention, they will not be further described here. Reference can be made to the foregoing application should any further information be desired. It suffices to note that the motor has the base arm M which is secured to the shell section 12 by screws S (FIGS. 2 and 3).

The motor is powered through a conventional electric cord 14 which enters the interior of the handle at the rearward end thereof and proceeds to an on-off switch 15, and thence to the motor through appropriate electrical conductors.

The section 12 of the combined handle and back member has on its underside the substantially at, planar surface 16, in the center of which is provided the generally longitudinally extending dovetail key 17. The screws S are recessed in the surface of key 17. As in the usual dovetail joint, the longitudinal side edges of the dovetail key 17 form with the surface 16 V-shaped grooves which run substantially parallel with one another. At the inner, or rearward end of the key 17 is a slightly offset surface 18, which has formed on it a transverse rib 19.

The brush head is indicated Igenerally by reference numeral 20. As can best be appreciated by reference to FIGS. 4 and 5, the brush head has the cavity 21, which forms with the t-op 'surface 22 of the brush head a female dovetail providing the ribs 23, which slidably mate with the grooves formed by the key. Bristles 24 are imbedded in the brush head.

At its rearward or inner end, the brush head has the fiat surface 25, which has formed thereon a transverse recess 26 of at least equal length with the rib 19 .and so positioned that when the brush is in its fully coupled position with the body 10, as illustrated in FIGS. 1 and 4, the rib 19 interts with the groove 26.

The brush head is provided with the offset vertical edge 27 (FIG. 4) which strikes against end 17a of the key to limit movement of the brush head toward the installed position. Additional stops are provided by the vertical joints between the -ofset portions respectively of the back and element, las indicated at 28 in FIGS. l and 3.

As can best be appreciated from FIGS. 2 and 5, the key 17 is formed with an internal cavity 29. Located in this cavity is the spring member 30, now to be described.

Referring to FIG. 2, it will be noted that -at the inner end of cavity 17 is located the post 31. This post is preferably formed as integral with the key member, `and is circular in cross-section. Inserted -over the post 31 is the loop portion 30a of spring 30. Diverging from the post on opposite sides of the motor 13 are a first leg 30b and a second leg 30C.

The leg 30b is a relatively long one and is provided with the central outwardly arched portion 30e. It terminates in a reversely offset portion providing an end 30d which is adapted to bear against the inside wall of the cavity 29, as seen in FIG. 2. The arched portion 30C is sufliciently arched that when the brush head is removed, the -arch will project well to the outside of the plane of the beveled side surface of the key through the side opening 32 therein. The arched portion 30C extends suiciently past the plane of the beveled edge of the key that when the brush head is engaged therewith, and pushed into its installed position, the spring is flexed by the action of the adjacent rib of the brush head, which is in compressive contact with the arched portion.

The construction of the key and brush head, particularly with reference lto the interengaging components of the dovetail joint, is such that when the faces 16 and 22 are in contact, the detent or rib 19 is engaged in groove 26. Any tendency of the faces to separate and of the rib to be disengaged from Ithe groove is overcome by the reactive forces produced by the flexing of the spring arm 30h. By 'virtue of the beveled surfaces in the dovetailed joint, it will be evident that the compressive force exerted by the spring against the side of the dovetail rib 23 will tend to draw the brush head surface 16 in closer contact with the lower surface 22 of the back. Consequently the spring tends to maintain the rib 19 and groove 26 in tight interlitting relationship.

When it is desired to separate the brush head from the back, all that need be done is to force the brush head to the left as viewed in FIGS. 1 and 4. Sui'icient force is exerted as to cause the groove to ride up over the rib. The resiliency of the spring arm 30h will permit the necessary deection of the brush head .and the brush head can then be slid ion-off and replaced or cleaned as desired.

As the brush head is installed, it will move toward the rear of the back and handle and as the surface 25 encounters the rib 19, that surface will ride lup over the rib. As the groove 26 comes into register with the rib, the spr-ing arm 30h will cause the groove to snap over the rib for the reasons earlier noted.

In addition to improving and maintaing the operative relationship between -the rib 19 and groove 26, the spring also serves to insure that the dovetail components will be maintained Iin tight relationship and that the mating edges of the brush head 20 and its back and handle member 10 will always be in abutting relationship when the brush head is on the brush.

From the foregoing it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth together with other advantages which are obvious and which are inherent to the structure.

It will be understood that certain features and subcombinations are of utility and may be employed Without refe-rence to other features and subcombinations. This is contemplated by and is within the scope lof the claims.

As many possible embodiments may be made of the invention without departing `from the scope thereof, it is `to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

Having thus described our invention, we claim:

1. A brush having a removable brush head, said brush including in combination,

a back member having a brush mounting side,

said side of said back member having a pair of V- shaped grooves running in the lengthwise direction of the back member and spaced laterally f-rorn one another, each groove having a pair of intersecting side walls,

a brush head having spaced rib members slidably received in said grooves,

resilient pressure means extending through an opening in the side wall of one of said grooves and frictionally engaging the rib surface adjacent said opening whereby to tend to spread said ribs and thereby bias said brush element toward said back member, and

cooperating detent and groove means located on said back member and brush head, said means being biased toward one another and into intertting engagement by the reactive forces produced by said pressure means.

2. A hair brush having a removable brush head, said hair brush comprising, in combination,

a back member having a brush receiving side,

a male dovetail key extending lengthwise on said brush receiving side, said key having opposite longitudinal side faces,

a detachable brush head, including bristles on one side and a female dovetail recess on the opposite side, said recess open at one end and mating with said key for relative sliding movement in a lengthwise direction relative to the back member, and

resilient means disposed Within said back member and extending through an opening in one key side face into compressive engagement with the adjacent surface of said brush head recess.

3. A hair brush as in claim 2 wherein said key has an interior cavity and said resilient means comprises a spring member having a leg anchored at one end and extending lengthwise of said key in said cavity, said leg having an intermediate arched portion extending sidewise through said opening in cotnact with said brush head recess surface.

4. A hair blush as in claim 3 wherein said spring member includes a second leg generally parallel with said firstmentioned leg in said cavity and adjacent the opposite side thereof, said legs are joined by a loop, and including a post in the cavity over which said loop is tted.

5. A hair brush Vas in claim 4 including cooperating detent and groove means located on said back member and brush head, said means being biased toward one another into intertting engagement by the reactive forces produced between the dovetail surfaces by said spring member.

References Cited by the Examiner UNITED STATES PATENTS 1,735,802 1l/l929 Statuto 15-176 1,887,913 11/1932 Bell 15-176 2,807,820 10/1957 Dinholfer 15-176 2,963,729 12/1960 Thonbo et al. 15-176 3,134,121 5/1964 Wachtel 15-176 FOREIGN PATENTS 339,485 12/ 1930 Great Britain.

CHARLES A. WILLMUTH, Primary Examiner. 

2. A HAIR BRUSH HAVING A REMOVABLE BRUSH HEAD, SAID HAIR BRUSH COMPRISING, IN COMBINATION, A BACK MEMBER HAVING A BRUSH RECEIVING SIDE, A MALE DOVETAIL KEY EXTENDING LENGTHWISE ON SAID BRUSH RECEIVING SIDE, SAID KEY HAVING OPPOSITE LONGITUDINAL SIDE FACES, A DETACHABLE BRUSH HEAS, INCLUDING BRISTLES ON ONE SIDE AND A FEMALE DOVETAIL RECESS ON THE OPPOSITE SIDE, SAID RECESS OPEN AT ONE END AND MATING WITH SAID KEY FOR RELATIVE SLIDING MOVEMENT IN A LENGTHWISE DIRECTION RELATIVE TO THE BACK MEMBER, AND 